On December 5, 2020, a capsule containing rock and soil from an asteroid named Ryugu landed in a barren region near Woomera, South Australia. The samples were collected by the Hayabusa 2 spacecraft which was launched by the Japanese space agency, JAXA from Tanegashima Space Center in Kagoshima on December 3, 2014.
What are the legal grounds for this sort of activity in outer space? In this article, I would like to introduce some basic rules for them.
Outer Space Treaty
The Outer Space Treaty was agreed by the United States, the United Kingdom and the Soviet Union on 27 January 1967. As of today, 110 countries including Japan are parties to the treaty.
Article 1 of the Treaty says ‘there shall be freedom of scientific investigation in outer space, including the moon and other celestial bodies…’ This appears to be the fundamental legal ground of this mission.
Article 2 says ‘outer space, including the moon and other celestial bodies, is not subject to national appropriation by claim of sovereignty, by means of use or occupation, or by any other means.’ Therefore, no country can claim sovereignty over a celestial body such as an asteroid.
How about taking rock and soil from an asteroid? Is it legal? As Ryugu is not owned by any country (see Article 2 above), their rock and soil are ownerless things. Therefore, if we adopt the internationally-recognised legal principle, JAXA would have acquired the ownership of the rock and soil by taking possession of them. According to the media, half the samples will be shared between JAXA, U.S. space agency NASA and other international organisations, and the rest kept for future study.
What happens, however, if they are not rock and soil but more marketable things such as rare metal? Will the same legal principle apply? Can countries and companies exploit space resources under Article 2 of the Treaty?
 The Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies. The full text is available here https://www.unoosa.org/oosa/en/ourwork/spacelaw/treaties/outerspacetreaty.html
 In Roman law, ownerless things became the property of the first person to take possession of them. See Article 239 of Civil Code in Japan.
Artemis Accords are an international agreement between the governments of participating nations in NASA’s Artemis program, which has the goal of landing ‘the first woman and the next man on the Moon by 2024’. The Accords were signed by the United States, Australia, Canada, Japan, Luxembourg, Italy, the United Kingdom, and the United Arab Emirates on 13 October 2020.
Among other things, Paragraph 2 of Section 10 of the Accords say ‘The Signatories affirm that the extraction of space resources does not inherently constitute national appropriation under Article 2 of the Outer Space Treaty…’. This provision seems to justify that countries and companies own and use resources that are derived from celestial bodies such as the Moon by declaring that space mining is not in conflict with Article 2 of the Treaty.
This is the US-led interpretation of Article 2 of the Outer Space Treaty, which Japan and six other countries accepted. We don’t know yet if the international consensus can be reached based on this interpretation. The competition for space resources seems to have already begun.
Luckily, we have a nice planetarium in Fukuoka City Science Museum to which I took my children several times. We can imagine the universe and think where human beings come from and where we go.
 The full text is available here https://www.nasa.gov/specials/artemis-accords/img/Artemis-Accords-signed-13Oct2020.pdf
Disclaimer: While every effort has been made to ensure that the information on this article is accurate at the time of posting, it is not intended to provide legal advice as individual situations will differ. If you do require advice or wish to find out more about the information provided and related topics, please contact the author.